Background Most running-related injuries (RRI) are attributed to training errors.

Objective This study investigated which running training characteristics are potential risk factors for RRI.

Design Prospective cohort study.

Setting Recreational distance runners.

Participants A total of 267 participants accepted to upload weekly all information about running training characteristics, other sport participation and injuries on a dedicated internet platform.

Risk factor assessment This 9-month follow-up investigated if the risk for RRI was influenced by some of the following running training characteristics: weekly volume (hours/week), weekly frequency (session/week), self-reported session intensity (CR10-Borg Scale), week-to-week absolute change in distance (km/week) and the concomitant use of different pairs of shoes (parallel use of a minimum of 2 different pairs of running shoes).

Main outcome measurements The primary outcome measure was total volume (hours) of running training and competitions (exposure) until the first RRI (Cox regression analyses). A RRI was defined as any physical complaint located at the lower limbs or lower back region, sustained during or as a result of running practice and impeding planned running activity for at least 1 day.

Results Overall, 89 participants (33%) recorded an RRI. The total incidence was 6.05 injuries per 1000h of exposure. The adjusted Cox regression analysis revealed that participants who practiced more than 2 hours/week were at a lower risk of RRI (Hazard ratio (HR): 0.539; 95% Confident interval (CI): 0.295-0.986) even when controlling for running experience and training regularity during the previous 12 months. The parallel use of more than one pair of running shoes (HR=0.600; 95% CI=0.369–0.975) and the week-to-week absolute change in distance (HR: 0.882; 68% CI: 0.836–0.931) were also protective factors, while previous injury was a risk factor (HR=1.841; 95% CI=1.185–2.860).

Conclusions This study identified training characteristics which are related to RRI risk.